Ingot casting



A. R. ROWE IINGOT CASTING Nov. 7, 1944.

Filed Aug. 17, 1945 5 mm E 11 16 MW m 9 N 4 z 1 7 i; 1 E 4: h z 6 o za arrays Era.

Patented Nov. 7, 1944i UNITED STATES PATENT OFFICE moor CASTING Andrew R. Rowe, McKeesport, Pa., assignor to Harbison-Walker Refractories Company, Pittsburgh, Pa., a corporation of Pennsylvania Application August 17, 1943, Serial No. 498,940

13 Claims.

This invention relates to the casting of metallic ingots.

The invention is applicable particularly to the casting of ingots of iron and steel, for which reason it will be described with particular reference to steel casting practice by way of illustrathe mold under a considerable head. This is dis-.

advantageous for various reasons. Thus, the relatively great head of the metal cause the stoolsto be cut out rather rapidly and it produces considerable splashing which may form a scabby surface and thus result in defects in the surface of product wrought from the ingot or necessitate chipping with added expense. Parfreely and slag or the like to collect at the sur face rather than being churned throughout the metal. Furthermore, it was intended that the ,float member should rise within the hot top as it was filled.

Experience has shown the ability of the hot top of that patent to achieve its intended results with some classe of steels or under some conditions, but that it wasopen to serious dis; advantages and drawbacks. One of the-most' erious of those was due tothe factthat the float either fitted closely toa tapered seat or within the walls of the hot top. As a result there was a tendency, particularly with certain classes of steels, such as low silicon steels, to be frozen into place in the bottom of the hot top due to the fact that the clearance between the side of the I floatand'the" hot top was so small that the metal ticularly, however, the metal in the mold is churned vigorously and deeply by the entering stream so that slag and other non-metallic material together with gases released from the metal are forced throughout the body of the metal within the mold. Such materials may not have sufii-cient buoyancy to rise to the surface so that undesirable non-metallic matter and blow holes will be present in the ingot.

-Another difiiculty encountered in ordinary .bottom of the hottop was objectionable because casting practice is'that of pipe formation. To

avoid this it is customary to provide the mold with a hot top, orfeeder, which in any of its conventional forms constitutes an extension of the mold that acts a a reservoir for a body of the molten metal to feed the ingot as it freezes and thus to avoid piping by filling the axialshrinkage cavity. Such hot tops do not, however. avoid the foregoing disadvantages of pouring practice because the metal is teemed directly from the nozzle through the feeder into the mold.

In my Patent No.'1,399.'798, granted December 13, 1921, I disclosed a method and means whose object'was to reduce the foregoing difficulties and disadvantages. In accordance with that invention a hot top, or feeder, member was provided at its lower end with inwardly projecting lug r members which acted as a seat for a refractory float. Either the float er the lug was perforated.

The underlying conceptiwa that by b ki i p the nozzle stream into a plurality of small streams the metal would enter the mold under a relatively slight head and would not cut out w the stool, splash objectionably, or penetrate the cast metal deeply, thus permitting gases to escape in.it froze easily. This condition was aggravated where the metal teemed was'on the low side of the pouring temperature range. Also, as the metal ran through the holes in the'floatmember it apparently created a downwardly active suc tion which tended to hold the float member in place. Even though gas escaped freely and slag or the like rose to the metal surfacathis tendency for the hot top and float to stay or'freeze in the thefioat would break off during and interfere with rolling, and this was aggravated where the perforation were in theshoulder because it then had to be of considerable width. sThe small clearance between the float and the hot top walls or its seat prevented successful 'dislodging of the float by means of a bar or lever. I Another disadvantage was that if. the ladle was not spottedo accurately the stream from the nozzlewould tend to pass directly through one of the holes through the plate or lug so that the metal would enter the mold under the greater part of it's normal head pressure,- thus partially defeatingthe aim of the invention. For these and related reasons:

the hot top of. that patent did not satisfactorily achieve itsobjects under theyconditionsawhich prevail in ordinary steel mill practicelandtheree fore it was not adopted commercially;-

It is among the objects of this invention to. 1 provide ingot casting means which-avoids orre-s; duces substantially the vtroublesrand disadvaneqnw tages described above, v i a A particular object is to provide up the stream of metal entering the mold in such manner as to permit escape of gas from an ingot feeder, or hot top, and the combination of an ingot. mold with a feeder, which satisfactorily breaks the metal and to avoid strong agitation of the body of metal within the mold so that slag andthe like is not entrapped within the body of the metal but rises freely to the surface, and pipe and blow hole formation together with rapid cutting out of the stool and production of scabby or'cracked surface are reduced or avoided.

Yet another object is to provide an ingot feeder having a float member which cooperates to break up the ladle stream for attainment of the foregoing object and which does not have the tendency to be frozen in place which characterized former feeders provided with float members.

Other objects will be understood from the following description.

The invention may be described in connection with the accompanying drawing in which Fig. 1 is a vertical sectional view, taken on the line 1-1, Fig. 2, showing one embodiment of the invention applied to a small-end-up mold; Fig. 2 a plan view of the mold and hot top shown in Fig, 1; Fig. 3 a view similar to Fig. 1 showing the mold and hot top filled; Fig. 4 a bottom view of the float plate member shown in Figs. 1 to 3; and Figs. 5 and 6 fragmentary vertical sectional views of modified forms of the hot top, and float member.

The present invention is predicated upon my discovery that the troubles described above can be repressed or overcome by the use of a float member which is soconstructed and arranged with respect to its supporting means at the bottom of the hot top that the metal poured from the ladle passesinto the mold around the sides of the float plate and drains freely between the plate and the supporting means. To this end the plate is of such size as to provide substantial clearance between its edges and the hot top walls, in contrast to the structure of my aforesaid patent. Preferably the float issupported on a shoulder formed interiorly of the hot top at or adjacent its lower end and means are provided for free drainage of the metal between the bottom of the plate and the hot top shoulder.

Having reference now to the drawing, Fig. 1 shows a hot top in accordance with the invention associated with a small-end-up mold I. The feeder comprises a tubular hot top member 2, made from fire clay or other refractory material,

which may take any of a variety of forms and be a supported on or by the mold in a variety of ways known in the art. Preferably, however, the lower end of the hot top is of such size as to enter the mold opening, and it'is provided on at least two of its opposed walls with exterior ribs 3 which, as seen particularly in Fig. 1, act to support the hot top, 1. e., the lower ends of ribs 3 rest upon the top of the mold and support the hot top properlypositioned with respect to the mold opening. At its lower end the hot top is provided with means, suitably a continuous inwardly extending shoulder 4, to support a float plate member 5.

In accordance with the present invention, and as indicated above, the float plate and the hot top are so constructed relative to one another that metal poured into the hot top enters the mold by flowing around the edges of plate 5, and in the embodiment shown it passes between the lower surface of the plate and its supporting shoulder 4. This may be accomplished by providing grooves in the upper surface of the shoulder which drain the metal flowing from clearance space 5, or by providing similarly acting grooves in the under side of plate 5, or, and preferably, by providing the upper surface of the shoulder and the lower surface of the plate with aligned grooved portions which cooperate to drain into the mold metal which flows over the plate and into clearance space 6.

In the embodiment shown in the drawing plate 5 is accordingly provided on its under surface centrally of each side with inwardl projecting grooves I, and shoulder 4 is provided with four grooves 8 which are positioned to lie beneath grooved portions 1 when the plate is centered within the opening of the hot top. Most suitably grooves 1 take the form of notches of arcuate cross section which decrease in width and depth passing inwardly from the edge of the plate.

In the use of the embodiment shown in Figs. 1 to 4 the hot top with float plate 5 is supported on mold i in the manner shown in Fig. 1. Metal is then teemed into the feeder from the nozzle 9 of a ladle, not shown. The large stream under its normal head strikes plate 5 and flows outwardly thereover to enter the clearance space 6 between the edges of the plate and th walls of the hot top, whence it drains in relatively small streams Ill into the mold. A primary action is that the breaking up of the main stream I I of the metal by plate 5 into a relatively thin layer which moves over the plate permits at least some portion of gas carried by the metal to escape before the metal enters the mold. This action is further enhanced by the passage of the metal from the hot top in a plurality of small streams, which permits a more ready escape of gas than is possible from the large stream H. The small streams l0 do not churn up the body of metal I 2 within the mold so that there is little tendency for gas bubbles to be stirred into the metal as it rises within the mold. Thus the feeder acts to reduce or eliminate blow hole formation.

Furthermore, streams l0 drain into the mold under a pressure head that is substantially less than the head of stream II from ladle 9. Thus there is reduced agitation of the body l2 of molten metal within the mold as compared with the stirring which results as the main stream Ii enters the mold directly. For the same reason the rate of cutting out of the stool is reduced substantially, and splashing of such intensity as to produce scabby surface is avoided and slag or other non-metallic material carried by the metal in the ladle has full opportunity to rise to the surface of the metal within the mold. These factors cooperate to improve the ingot quality.

The ingot is teemed until the lower end of the hot top member 2 is immersed within the surface of the body of metal l2 within the mold. When the metal between the hot top and the mold wall has frozen, as indicated in Fig. 3, further metal is poured into the hot top to fill it and provide a reservoir (Fig. 3) for feeding the ingot as solidification progresses, to reduce or eliminate piping. A major advantage of the present invention is that the tendency of the float member to freeze to the bottom of the hot top that has been encountered in prior art structures isovercome. Thus, as the hot top is fllled the passage of metal around the platein clearance space 6 and through the grooved portions creates a buoying eifect upon the plate s that it rises with the level of the metal within7the hot top, as shown in Fig. 3. I now believe that the notching of plate 5 which is shown in the drawing is particularly desirable because the shape is such that as the metal flows through these notches the buoyant effect is intween the plate and the hot top walls avoids freezing where, as may happen, the metal is poured on the low side of the range of pouring temperature, or with steels which tend to freeze readily. The float plate may be tilted and lifted by tongs from the hot top member after the latter has been filled as shown in Fig. 3, so that it may be'reused with another member 2, thus reducing the expense of hot topping. Or, as may be preferred in some instances it may be allowed to remain in place for the purpose of keeping the body of metal within the hot top member molten to insure maximum reduction of piping. An advantage of theform of hot top shown in Figs. 1 to 3 is that the operator can view the interior of the mold through the space between the outer walls of the hot top and the mold wall and thus determine when the metal has been poured to the proper height, which is not possible, or at least not convenient, with some forms of hot 1 1 To insure drainage of the metal from clearance space 6 so that-there will be no danger that plate 5 will freeze'to its supporting shoulder or to the hot top,wall in the interval when the feeder-is being frozen in place in the mold, the upper surface of the shoulder 4a may be sloped downward- I ly and inwardly as indicated at I5, Fig. 5. Free drainage of metal from the hot top to avoid freezing of the float to its shoulder can be provided ill Kin

in other ways also. For example, instead of providing the plate and shoulder with grooves, or tapering the shoulder inwardly as shown in Fig. 5,

the upper surface of the shoulder may be formed as shown in Fig. 6. As there shown the hot top 2b is'provided at its bottom with a shoulder 4b which extends inwardly from each side of the hot top. Along each side of the hot top the upper surface of shoulder 4b slopes downwardly from each end, so that the upper surface is of flat V-form, as shown at l6, Fig. 6. The shoulder forms of Figs. 5 and 6 are especially desirable because they insure free drainage of metal from the hot topinto the mold and this coupled with point support of the float at its comers more certainly insures that the float will not freeze. to the shoulder.

Various other modifications are, of course, permissible without departing from the spirit of the invention. For example, instead of providing the passage between the float and the supporting shoulder as described above, the lower side of the plate may carry bosses I I, Fig. 5, suitably situated adjacent the corners of the plate. As will be understood, the same result can be had by forming the bosses at similar positions of the supporting shoulder instead of on the plate, and such' bosses may be used with any of the shoulders described above. Also, although in Figs. 1 to 3 the grooved portions of the plate and supporting shoulder cooperate to provide four passageways for metal, it will be understood that for some purposes fewer or more passageways may be provided. Similarly, the hot top may be blocked up from the top of the mold in accordance with practice in some clu plants to avoid the formation of hanger cracks, but that and related details of casting practice are not involved in the present invention and therefore need notbe described.

In addition to eliminating the formation of surface scabs the invention otherwise improves the surface quality of Thus, in ordinary practice the heavy head of metal from the nozzle coupled with the relativelysmall area of the mold opening causes the metal in the mold to surge upwardly along the mold sides above the natural level of metal in the mold. The thin skin of metal forced up the 'side of the mold in this manner freezes so quickly that contraction of it may cause cracks to form which impair the surface of the ingot. Such cracks may extend as much as several inches into the ingot and affect the quality of products made from it. In the practice of the present invention the metal enters the mold under such a low head pressure that there is little or no tendency for such surface cracks to form.

Although the invention has been illustrated as applied to small-end-up molds of generally rectangular cross section it is to be understood that it is applicable generally to ingot casting irrespective of the type of mold or its cross sectional character.

According to the provisions of the patent statutes, I have explained the principle and mode of use of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. An ingot casting apparatus comprising a refractory tubular hot top having at its lower end an inwardlyprojecting member for carrying a plate member, a refractory plate member disposed within said hot top and adapted to rest upon said inwardly projecting member with its edges spaced from the walls of the hot top to provide substantial clearance for molten metal poured into the hot top to pass, therebetween, and one of said members being provided with means providing for free drainage of metal into the mold from the space-between the edges of said plate and the hot top walls.

2. An ingot casting apparatus comprising a refractory tubular hot top adapted to be carried by the top of a .mold to form a continuation thereof, said hot top having at its lower end an inwardly projecting member for supporting a 5:

' with 'its edges spaced from the walls of the hot top to provide a passageway of substantial width for molten metal poured into the hot top, and one of said members being provided with means providing for free drainage of metal through said passageway into the mold.

3. An ingot casting apparatus comprising a refractory tubular hot topadapted to be carried by the top of a mold to form an upward extension of the mold and with its lower end disposed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder member. a refractory imperforate plate member disposed within said hot top and adapted to rest upon said shoulder with its edges spaced from the walls of the hot top to provide a passageway of substantial width for molten metal poured into the hot top, and at least one of said mema said shoulder withlts walls of the hot top to rest upon said shoulder with bers being provided with at least one groove for passage of said metal between the members from the hot top into the mold.

4. An ingot casting apparatus comprising a refractory tubular-hot top adapted to be carried by the top of a mold to form an upward extension of the mold and with its lower end disposed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder memoer whose upper surface slopes downwardly and refractory tubular hot top having at its lower end an inwardly projecting shoulder member, a refractory imperforate plate member disposed within said hot top and adapted to rest upon edges spaced from. the to provide a passageway of substantial width for molten metal poured into the hot top, and at least one of said members being provided with at least one groove for passage of said metal between the members from the hot top into the mold.

6. An ingot casting apparatus comprising a refractory tubular hot top adapted to be carried by the top of a mold to form a continuation thereof and having at its lower end an inwardly projecting shoulder member, a refractory imperforate plate member disposed within said hot top to rest upon said shoulder with its edges spaced from the walls of the hot'top to provide a passageway of substantial width for molten metal poured into the hot top, and the bottom of said plate member and the upper surface of said shoulder being provided with cooperating grooves to provide passages for said metal between the members from the hot top into' the mold. 1

7. An ingot casting apparatus comprising a refractory tubular hot top adapted to be carried by the top of said mold to form a continuation thereof and having at its lower end an inwardly projecting shoulder member, a refractory plate member disposed within said hot top and adapted its edges spaced from the walls of the hot top to provide passageway for molten metal poured into the hot top, and the bottom of said plate member being provided with arcuate cross section notches to provide passages for said metal between the members from the hot top into the mold.

8. An ingot casting apparatus comprising a refractory tubular hot top adapted to be carried by the top of a mold to form an upward extension of the mold and with its lower end disposed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder member whose upper surface is provided with spaced grooves, a refractory imperforate plate member disposed within said hot top to rest upon said shoulder with its edges spaced from the walls of the hot top to provide passagewa for molten metal poured into the hot top, and the bottom of said plate member being provided with arcuate cross section notches cooperating with said grooves to provide passages for said metal between the members from the hot tbp into the mold.

9. An ingot casting apparatus comprising a refractory tubular hot top having at its lower end inwardly projecting means for supporting a plate member, and a refractory imperforate plate member disposed within said hot top to rest upon said shoulder with its edges spaced from the walls of the hot top to provide a passageway of substantial width for molten metal poured into the hot top, and said plate member being provided on its bottom surface with notches extending inwardly from the-plate edges, said notches being of arcuate cross section and of progressively decreasing width anddepth inwardly from said edges.

10. An ingot casting apparatus comprising a refractory tubular hot top adapted to be carried by the top of said mold to form an upward extension of the mold and with its lower end dis posed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder member whose upper surface is provided with spaced grooves, a refractory imperforate plate member disposed within said hot top and adapted to rest upon said shoulder with its edges spaced from the walls of the hot top to provide passageway for molten metal poured into the hot top, and said plate member being provided on its bottom surface with notches extending inwardly from the plate edges, said notches being of arm-- ate cross section and of progressively decreasing width and depth inwardly from said edges and being disposed to cooperate with said grooves to provide passages for said metal between the mem bers from the hot top into the mold.

11. The combination with an ingot mold of a refractory tubular hot top carried by the top of said mold to form an upward extension of the mold and with its lower end disposed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder member whose upper surface is provided with spaced grooves, a refractory imperforate plate member disposed within said hot top and adapted to rest upon said shoulder with its edges spaced from the walls of the hot top to provide passageway for molten metal poured into the-hot top, and the bottom of said plate member being provided with grooves cooperating with said shoulder grooves to provide passages for said metal between the members from the hot top into the mold.

12. The combination with an ingot mold of a refractory tubular hot top carried by the top of said mold to form an upward extension of the mold and with its lower end disposed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder member whose upper surface slopes downwardly and inwardly, a refractory imperforate plate member disposed within said hot top and adapted to rest upon said shoulder with its edges spaced from the walls of the hot top to provide a passageway of substantial width for molten metal poured into the hot top, and the bottom of said plate member being provided with grooves to provide passages for said metal between the members from the hot top into th mold.

13. The combination with an ingot mold of a refractory tubular hot top carried by the top of said mold to form an upward extension of the mold and with its lower end disposed in the mold opening, said hot top having at its lower end an inwardly projecting shoulder member provided on its upper surface with spaced grooves, a reiractory impertorate plate member within said. hot top and adapted to rest upon said shoulder with its edges spaced from the walls of the hot top to provide passageway tor molten metal poured into the hot top, and said plate member being provided on its bottom suriace with notches extending inwardly from the plate edges,

top into the mold. V

ANDREW R. ROWE. 

